1. Field of the invention
The present invention relates to an LCD having an integrated amorphous-silicon TFT row driver, and more particularly to an LCD having an integrated amorphous-silicon TFT row driver, in which a drive IC is replaced with a shift register integrated in an LCD panel.
2. Description of the Prior Art
Generally, a TFT-LCD includes a TFT, which is a switching device, a capacitor and an auxiliary capacitor, which are formed by liquid crystal filled between upper and lower electrodes, a gate electrode for managing on/off of the TFT, and an image signal electrode. A transistor is turned on when voltage is applied to a gate of the TFT forming pixels by means of external peripheral circuits so that image voltage can be applied to liquid crystal. After storing image information in liquid crystal by applying image voltage to liquid crystal, the transistor is turned off, so the charges stored in the liquid crystal capacitor and the auxiliary capacitor are preserved, thereby displaying an image for a predetermined time. When voltage is applied to liquid crystal, alignment of liquid crystal varies. In this state, if light passes through liquid crystal, diffraction may occur. Accordingly, desired images can be obtained by passing diffracted light through a polarizing plate.
However, the LCD uses a drive IC at a gate PCB so as to supply drive pulse to a gate line. Therefore, a pad section and a fan-out section are required in order to mount the drive IC, so that it is difficult to fabricate the LCD in a compact size. In addition, due to the drive IC, manufacturing cost and weight of the LCD are increased.
For this reason, as shown FIGS. 1 and 2, a COF (chip on film) type LCD, in which a PCB is removed from the LCD panel through a COF process, or an LCD having an integrated amorphous-silicon TFT row driver, in which the drive IC is replaced with a drive circuit integrated in the LCD panel, have been proposed in order to fabricate the LCD in a compact size and to reduce manufacturing cost and weight of the LCD.
In order to integrate the drive circuit in the LCD panel, a shift register is necessarily required for shifting a phase of gate drive pulse in a gate line direction according to a clock period. At this time, the drive circuit includes four transistors and two capacitances. In addition, rope potential is stabilized by means of a reset terminal.
However, according to the conventional technique, if a reset operation is not carried out at a final terminal of the LCD panel, signals are distorted as a gate drive period repeats, so the shift register is malfunctioned.